The bell rang and the class was over. The classroom became noisy. Some students went out of the classroom. I was just chatting with some of my classmates when Li Hong came to me. She smiled and said to me, "What's four minus four? Do you know?" "It's zero. That is easy." answered I. But Li Hong shook her head and said "It's wrong. It's eight." "Why? That's impossible!" "You will understand if you cut down four corners of a desk." said Li Hong. "Is that a joke?" "Oh, yes." We all laughed. During the class break, we had a good rest. We often have a pleasant break. 铃一响，下课了。教室里热闹起来，一些学生出了教室。当李红向我走来时，我正和一些同学聊天。她笑着对我说：“你知道4减4等于几吗?”我回答：“等于零，太简单了。”但李红播着头说：“不对，是8。”“为什么?不可能。”李红说：“你砍掉桌予的4个角，就明白了。”“这是笑话吗?”“唤，是的。”我们都笑-了。课间我们放松了。我们经常度过愉快的课间。